Spectroscopy and Photophysics of 1 Pi sub g and 3 Pi sub g Rydberg, Ion-Pair States of Cl2, Revealed by Multiphoton Ionization

摘要

Mass-resolved, two photon resonant, three photon ionization of jet-cooled Cl2 has been used to study the spectroscopy and photophysics of the lowest energy, double-well 1 pi g and 3 pi g states of mixed Rydberg (4 sigma) and ion-pair character. Inner well levels from v' = 0 (64 027/cm) to v' = 15 (73 343/cm) have been observed for 1 pi g of the mass 70 molecular chlorine isotope. Inner well levels for 3 pi g have been observed from v' = 0 at 63 472/cm to the top of the barrier, and well beyond that to levels spanning both wells. Observation of these long progressions is attributed to excitation via a repulsive continuum at a well-phonon level. The photophysics of this latter process as well as the mechanism for copious atomic ion formation are discussed. Variation of linewidth with vibrational quantum number due to the predissociation of inner well levels is observed and attributed to repulsive valance states. The data are in good agreement with the theoretical calculations of Peyerimhoff and Buenker, and Tuckett and Peyerimhoff. Multiphoton ionization, Rydberg states, Ion pair states, Molecular chlorine, Vibrational progression. (mgm)